Recebendo Mensagens via Webhook

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import express from "express";
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import crypto from "node:crypto";
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const app = express();
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function verifySignature(rawBody, signature, secret) {
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  if (!signature?.startsWith("sha256=")) return false;
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  const expected = crypto
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    .createHmac("sha256", secret)
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    .update(rawBody)
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    .digest("hex");
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  return crypto.timingSafeEqual(
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    Buffer.from(signature.slice(7)),
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    Buffer.from(expected)
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  );
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}
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// Use raw body parser para preservar os bytes originais na verificação de assinatura
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app.post(
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  "/webhooks/whatsapp",
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  express.raw({ type: "application/json" }),
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  (req, res) => {
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    // 1. Verificar assinatura
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    const signature = req.headers["x-muchaw-signature"];
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    if (!verifySignature(req.body, signature, process.env.MUCHAW_WEBHOOK_SECRET)) {
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      return res.status(401).json({ error: "Assinatura inválida" });
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    }
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    // 2. Responder imediatamente (antes de processar)
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    res.sendStatus(200);
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    // 3. Parsear e processar
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    const event = JSON.parse(req.body.toString());
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    handleEvent(event);
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  }
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);
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function handleEvent(event) {
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  switch (event.event) {
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    case "message.received":
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      console.log("Nova mensagem de", event.data.fromNumber, ":", event.data.body);
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      break;
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    case "message.delivered":
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      console.log("Mensagem", event.data.id, "entregue");
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      break;
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    case "message.read":
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      console.log("Mensagem", event.data.id, "lida");
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      break;
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    case "message.failed":
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      console.error("Falha na entrega da mensagem", event.data.id);
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      break;
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  }
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}
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app.listen(3001, () => console.log("Servidor de webhook na porta 3001"));